[Andy Baker]

Here is some experience with t-slot type fasteners on FIRST robots:

1. We have had steel t-slots nuts rip through the side wall of t-slots.

2. Universal fasteners have backed out of their milled hole, even when the hole is machined properly and tightened accordingly.

3. We sometimes have to drill thru the entire extrusion and put a nylock nut on the back side of a joint that is under a very heavy load.

There are factors which FIRST robot designers have to consider which industrial equipment designers don't (at least not as much).

This 130 lb. weight limit is difficult to deal with. During the week before shipping, we will all be looking for ways to lose 2-8 pounds of weight on these robots. Sometimes a through bolt and a nylock nut is lighter than a automatic fastener.

In my 10 years of experience designing industrial equipment with t-slot type extrusion, I have not seen an industrial application that even comes close to a FIRST robot when it comes to vibration and dynamic loading.

One of the tips that FIRST gives new teams competing in FIRST is this:

"You are not ready to ship your robot until you drive it full speed into a brick wall three times w/o any problems."

You can bet on this: there will be some machines that will be travelling up to 15 feet/sec, banging into the goals, other robots, and the field border. Parts will be left on the field.

As for team 45, we won't be using any automatic fasteners on our robot this year. I'm not saying that they wouldn't work, 'cause we haven't tried them on a FIRST robot. Please let us know if they do for FIRST robot applications. I know they work well for industrial equipment, but that is a different story.

Andy B.